Telephony services provide enhanced functionality to telephone service subscribers. Call waiting, for example, enables subscribers at least some ability to manage multiple incoming calls. Whereas telephony services were implemented on one or a very limited number of network types historically, the advent of digital telephony and mobile telephony has resulted in the provision of basic telephony capability through a variety of networks. While the emergence of different types of telephone networks has been beneficial to subscribers generally, it has resulted in increased complexity for subscribers and consumers in the context of value added telephony services and features. As an example, a subscriber or other user who uses two or more types of telephony networks may have to duplicate efforts when implementing and maintaining various services and features such as address books, call waiting, Caller ID, and so forth.